4, 3, and 2? 8, 9, and 10? Are 7, 6, 3, and 2? Are Are 4, 3, 2, and 1? Are 12, 11, 10, and 9? 10. How many are 6 times 3? 7 times 8? 9 times 7? 7 times 6? 7 times 9? 7? 12 times 12? 6 times 4? 6 times 7? 12 times 7? 9 times 5? 8 times 7? 12 times 11? 8 times 5? 3 times 11. How many times 2 in 12? 2 in 18? 2 in 24? 3 in 6? 3 in 12? 3 in 36? 4 in 20? 4 in 32? 4 in 48? 5 5 in 60? 6 in 36? 6 in 48? 6 in 72? in 25? 5 in 35? 7 in 14? 36? 11 in 55? 8 in 96? 9 in 11 in 132? 7 in 56? 7 in 84? 8 in 40? 9 in 108? in 144 ? 11 in 22? 12 Note.-Younger pupils should be required to review and dwell on the preeding questions for illustration, and the tables, till their solutions be made perfectly familiar. NUMERATION. TV. Q. When I say to you," Give me that book," do I mean one book, or more than one? Q. When we speak of a single thing, then, what is it called? Q. What are one unit and one more, or one and one, called? Q. What does the letter I stand for? Q. What does the letter D stand for? Q. What does the letter M stand for? Q. You said that V stands for five; suppose you place the letter] before the V, thus, IV, what will both these letters stand for then? A. Only four. Q. What, then, may be considered as a rule for determining the value of these letters? A. A letter standing for a smaller number, and before a larger, takes out its value from the larger. Q. One X stands for ten; what do two X's stand for? A. Twenty. Q. What, then, is the value of a letter repeated? A. It repeats the value as often as it is used. Q. Will you name them? A. I, V, X, L, C, D, M. Q. What is this method of expressing numbers by letters called? A. The Roman method. Q. Why called Roman? A. Because the Romans invented and used it. Repeat the ¶ VI. We have a shorter method still, which is in very general e, as will appear by observing what follows A. Figures. Q. By what other name are they sometimes called? A. The 9 digits. Q. What is this method of expressing numbers called? A. The Arabic method. Q. Why so called? A. Because the Arabs are supposed to have invented it.* Let me see you write down on the slate, in figures, the numbers one, two, three, four, five, six, seven, eight, nine. Q. To express ten, as we have no one character that will do it, what two characters do we make use of to represent this number? A. The first character, 1, and 0 or cipher; thus, 10. Q. What place does the 0, or cipher, in this case take? Q. What place does the figure 1 take? A. A new place. Q. What is this new place called? A. The tens' place. Q. Write down in figures, on the slate, the number ten, now take away the 1, and what will be left? A. Nothing but 0, or cipher. Q. What is the value of this 0, or cipher, thus standing alone? Q. Now place the 0 at the right of the figure 1, and what will it become Q. How was it obtained from the Arabs? A. The Moors communicated it to the Spaniards, and John of Basingstok Archdeacon of Leicester, introduced it into England; hence its introducti into our own country. Q. About what time was it introduced into England? A. About the middle of the eleventh century. Q. How extensively is it now used? A. All over the civilized world Q. How many times is the figure 1 increased by the 0, or cipher? A. Ten times. Q. What effect, then, has a cipher, in all cases, when placed at the right of figures? A. It increases the value ten times. Q. In what proportion is this increase said to be? As you have probably learned by this time how to write down ten in figures, by the help of a cipher, and learned also the value of this cipher, we will now proceed to higher numbers; and to begin: let me see you write down in figures, on the slate, the following numbers, viz. Q. Here we see the value of the cipher again; for, by placing a cipher at the right of ten, it becomes one hundred, (100,) that is, ten tens: should we place another cipher still at the right of the 100, (thus, 1000,) what would it become? A. One thousand, (1000.) Q. From what you have now seen of the value of figures, what may 2 and 5 be made to stand for? A. 25 or 52. Q. What is this different value called, which arises from the figures being placed or located differently? A. Their local value. Q. What would be the value of the five written alone? A. Simply 5. Q. What is the value, then, of a figure standing alone? 4. The simple value. Q. How many values do figures appear to have? A. Two. Q. What are they? A. Simple and local. Q. Now, as it takes 10 units to make one ten, or one in the next lefthand place, and 10 tens to make 100, how do figures appear to increase by being removed one place farther to the left? A. In a tenfold proportion, from right to left. You must have acquired, by this time, some considerable knowledge of figures: let me examine you a little; and, in the first place, let me see you write down on the slate the figure 4. Q. What do you call it? A. 4 units. Write at the left of the 4, the figure 3, (thus, 34.) Q. What do you call them both, and how are they read ? A. 4 units and 3 tens read thirty-four. Write at the left of the 34 the figure 8, (thus, 834.) Q. What do you call the three figures now, and how are they read? A. 4 units, 3 tens, and 8 hundreds, read eight hundred and thirty-four. Write at the left of 834 the figure 1, (thus, 1834.) Q. What do you call the 4 figures now, and how read? A. 4 units, 3 tens, 8 hundreds, and 1 thousand, read one thousand eight hundred and thirty-four. Q. We have now been combining, or placing figures together, till we have obtained the number 1834, representing the number of years it is since Christ appeared on earth, to the present time. We might continue to put figures together in this way, that would express higher numbers still, up to billions, &c. That you may be able to form some idea of the power of figures, let me tell you that there is not a billion of seconds in thirty thousand years; notwithstanding there are 60 seconds in every minute, 60 minutes in every hour, 24 hours in every day, and in a solar year, 365 days, 5 hours, 48 minutes, and about 48 seconds. Should we continue to go on as we began, in combining more figures still, it would be very inconvenient: to avoid this, we have a rule by which we can read almost any number of figures, ever so large. What is this rule called? A. Numeration. Q. What is the reading or expressing a number by figures, as now shown, called? A. Notation or Numeration. RULE. Q. From the above illustrations, how does it appear that you musi begin to numerate ? A. Begin at the right hand. Q. At which hand would you begin to read? A. The left. |